目的 了解托幼机构及中小学发生诺如病毒(Norovirus,NoV)聚集性疫情期间集体机构及家庭中的密切接触者病毒感染及环境污染情况.方法 2017-2019年在上海市徐汇区托幼机构及中小学发生的NoV聚集性疫情期间,通过现场流行病学方法分析机构密切接触者NoV感染率和环境检出率.选取疫情中NoV确诊病例的家庭,经知情同意采集家庭密切接触者的粪便,并上门采集环境标本,计算家庭密切接触者NoV感染率和环境检出率.采用SPSS 18.0软件进行x2检验和Fisher确切检验,使用GraphPad Prism 8绘制率的比较图.结果 76起机构疫情中共采集密切接触者标本405份,NoV感染率为20.25％(82/405),41个确诊病例家庭中采集密切接触者标本119份,NoV感染率为9.24％(11/119),两组差异有统计学意义(x2=7.63,P=0.01).采集集体机构环境标本372份,NoV检出率为4.03％(15/372),采集家庭环境标本123份,NoV检出率为8.94％(11/123),两组差异有统计学意义(x2=4.48,P=0.03).集体机构环境标本NoV检出率场所从高到低分别为马桶(10.17％)、呕吐地面(9.68％)、洁具(8.00％)、教室门把手(5.88％)和厕所水龙头(5.41％).家庭环境标本NoV检出率场所从高到低分别为马桶(14.63％)和洁具(12.20％),未在手接触部位检出NoV.结论 在集体机构发生NoV聚集性疫情时,可导致机构和家庭中一定比例的密切接触者感染NoV,且均可在环境中检出NoV,马桶和洁具污染尤为严重.应加强校内密切接触者管理和家庭成员的健康教育,规范机构消毒并指导家庭消毒.

[目的]评估托幼机构和中小学诺如病毒疫情期间,感染诺如病毒儿童排毒时长及影响排毒时长的可能因素,为疫情防控提供科学依据.[方法]2017—2019年,采集上海市徐汇区托幼机构和中小学校诺如病毒疫情疑似病例及密切接触者标本,应用实时荧光定量逆转录聚合酶链反应(real-time RT-PCR)方法检测样本诺如病毒带毒情况.对感染诺如病毒儿童经知情同意后每隔3～7 d采样,直至样本检测阴性.[结果]研究期间,共报告76起诺如病毒感染聚集性疫情,涉及1014例疑似病例,对421名疑似病例标本检测,诊断出311名确诊病例.经知情同意后,共有58名确诊病例参与排毒研究,参与率为18.65％.诺如病毒感染者平均排毒时间为(16.24±13.80)d,排毒时间超过7 d病例占79.31％,超过14 d占37.93％,超过21 d占17.24％.Cox比例风险模型结果显示,症状较严重者(HR=2.06,P=0.040)、托幼儿童病例(HR=4.13,P=0.012)和2019年确诊病例(HR=0.11,P<0.001)排毒时间更长.[结论]感染诺如病毒的学龄儿童返校后的一段时间内仍存在持续排毒,从而导致疫情传播风险,建议在病例返校后做好排泄物的消毒处理,避免疫情的二次传播和蔓延.

目的 分析一起托幼机构诺如病毒感染聚集性疫情期间诺如病毒感染者持续排出病毒的情况,为卫生行政部门的疫情防控提供科学依据.方法 以上海市徐汇区发生诺如病毒感染的1所托幼机构为研究点,采用现场流行病学方法采集疑似病例、密切接触者、环境标本及相关资料,使用Read-time RT-PCR检测标本诺如病毒带毒情况.对诺如病毒感染者的实验室诊断病例每隔3～7d采样,直至样本检测阴性.结果 疫情共报告14例急性胃肠炎病例,其中12例实验室诊断病例平均排毒时间为(26.58± 17.94)d.12例持续排毒的病例中,9例排毒时间超过7d,8例排毒时间超过14 d,7例排毒时间超过21 d.结论 感染诺如病毒的儿童排毒时长,远超其隔离时间.病例返园后仍应加强病例的管理、消毒和疑似病例的检索工作.

Norovirus (NoV) is recognized as a leading cause of acute gastroenteritis (AGE) outbreaks in settings globally. Studies have shown that employees played an important role in the transmission mode during some NoV outbreaks. This study aimed to investigate the prevalence of NoV infection and duration of NoV shedding among employees during NoV outbreaks, as well as factors affecting shedding duration. Specimens and epidemiological data were collected from employees who were suspected of being involved in the transmission or with AGE symptoms during NoV outbreaks in Xuhui District, Shanghai, from 2015 to 2017. Specimens were detected using real-time RT-PCR to determine whether or not employees had become infected with NoV. Specimens were collected every 3–7 days from NoV-infected employees until specimens became negative for NoV. A total of 421 employees were sampled from 49 NoV outbreaks, and nearly 90% of them (377/421) were asymptomatic. Symptomatic employees showed significantly higher prevalence of NoV infection than asymptomatic ones (70.5% vs. 17.0%, P < 0.01). The average duration of NoV shedding was 6.9 days (95% confidence interval: 6.1–7.7 days) among 88 NoV-infected individuals, and was significantly longer in symptomatic individuals than in asymptomatic ones (9.8 days vs. 5.6 days, P < 0.01). In Cox proportional-hazards model, after adjusting age and gender, symptoms was the only factor associated with duration of NoV shedding. Compared with asymptomatic employees, symptomatic employees had higher prevalence of NoV infection and longer durations of NoV shedding. Since NoV shedding duration among NoV-infected employees tends to be longer than their isolation time during outbreaks, reinforcement of hygiene practices among these employees is especially necessary to reduce the risk of virus secondary transmissions after their return to work.

目的 了解上海市徐汇区急性呼吸道感染病毒病原学现况.方法 2012-2016年收集监测点医院流感样病例咽拭子标本,采用Real-time RT-PCR方法检测.结果 对4 660份标本进行流感检测:flu A 18.80％,flu B 6.78％.对364份标本中进行7种呼吸道病毒PCR阳性率18.68％,其中flu A+flu B 10.44％,HRV 2.75％,ADV、HBoV和PV1型均为0.82％;RSVB 0.55％,PV2、PV4均为0.27％,hmPV未检出.比较一个流行年不同监测点流感检出率无差异.2012-2016年聚集性流感样病例疫情11起,集中在冬春季,流感占90.91％,无暴发疫情.结论 徐汇地区呼吸道病毒多样化,流感病毒最常见,且呈冬春季和夏季双峰流行,B型、季H3型、新HIH1型交替,夏季高峰多以季H3型为优势毒株.流感样病例就诊百分比与流感病毒检出率呈正相关.学校、托幼机构为呼吸道病毒感染聚集疫情重点防控单位.应长期监测主要呼吸道病毒活动水平.

目的 通过分析HEV的5′-UTR基因序列,确定上海市徐汇区手足口病(HFMD)病例中HEV的型别.方法 采集2012年HFMD患儿标本,采用Real time-RT-PCR分别检测HEV、EV71和CoxA16核酸,初步鉴定其型别.从中挑选未能分型的HEV毒株扩增其5′-UTR进行核苷酸序列测定,运用DNAStar和MEGAS.2软件进行序列分析.结果 26例标本均为HEV阳性:10例EV71阳性,5例CoxA16阳性,11例其他型HEV阳性.扩增11例未能分型的HEV标本的5 ′-UTR序列,9例测序成功,通过序列比对确定病毒型别:CoxA16 8例,CoxA10 1例.结论 上海市徐汇区HFMD患儿的主要病原是EV71和CoxA16,也存在着其他型别的HEV,如CoxA10,应加强HEV基因亚型的分布及流行特点的监测.

目的 研究分析致泻性大肠埃希菌对于各类抗生素的敏感,了解可能存在的β-内酰胺酶超广谱耐药.方法 通过对医院肠道监测点的腹泻病例的病原学监测获得的三类致泻性大肠埃希菌,采用11种抗生素药敏纸片和MIC法进行抗生素药敏检测,用PCR法对可能的β-内酰胺酶超广谱耐药株进行分型检测.结果 致病性大肠埃希菌和聚集性大肠埃希菌的耐药较产毒素性大肠埃希菌多,在此二类大肠埃希菌(EAEC和EPEC共50株)中有7株有β-内酰胺酶超广谱耐药,分型以CTX-M-1型为主.结论 各类致泻性大肠埃希菌的抗生素敏感情况有明显差异,应对致泻性大肠埃希菌中存在β-内酰胺酶超广谱耐药情况引起重视,加强对致泻性大肠埃希菌耐药的持续监测.

AIM:To characterize the prevalence of hepatitis C virus(HCV)infection among Chinese intravenous drug users(IDUs).METHODS:A total of 432 adult IDUs(95 women and337 men)in Shanghai were included in the study.The third-generation Elecsys Anti-HCV assay(Roche Diagnostics GmbH,Sandhofer Strasse 116,D-68305,Mannheim,Germany)was used to screen for antibodies against HCV.The RIBA strip,a supplemental antiHCV test with high specificity,was performed on all of the samples that tested positive during the initial screening.All of the anti-HCV positive samples were analyzed with a Cobas TaqMan 48 Analyzer(Roche Diagnostics)for direct detection of HCV RNA.All of the HCV RNA-positive samples were sequenced for genotype determination.RESULTS:The preliminary screening identified 262(60.6%)subjects who were seropositive for HCV.Of the 62 females and 200 males seropositive subjects,16(16.7%)and 65(19.3%),respectively,were confirmed by RIBA,yielding an overall HCV seropositive rate of18.8%.Four female(6.5%)and 14 male(7.0%)subjects tested positive for HCV RNA,indicating an active infection rate of 4.2%for the entire study population.The 18 HCV RNA-positive serum samples were genotyped.Seven individuals were genotype 1b,and four were genotype 1a.One individual each was infected with genotypes 2a,2b and 3a.Four subjects were coinfected with multiple strains:two with genotypes 1a and 2a,and two with genotypes 1b and 2a.The active infection rate among HCV-seropositive individuals was22.2%,which was significantly lower than most estimates.CONCLUSION:The prevalence of HCV is relatively low among IDUs in Shanghai,with a spontaneous recovery rate much higher than previous estimates.

Objective:To study the association of Enteroaggregative Escherichia coli(EAggEC) virulence genes and bio-film formation.Methods: Biofilm formation test was used to screen EAgg EC and PCR was used to detect Agg R,AAT(CVD432),agga(Aggregative fimbria I),aafa(AAF/II),agg3a(AAF/III),pilS(Type IV pilus),pet(Plasmid-encoded toxin),eastA(EAggEC heat-stable toxin) genes and the relation between bio-film formation and virulence genes was analyzed.Results: Bio-film formation test can be used for screening of EAgg EC,which can be classified by virulence genotyping.Conclusion: Biofilm formation test is useful to screen Enteroaggregative Escherichia coli(EAggEC),and it has correlation with every virulence gene to varying degrees.

Objective:To analyze the situation of Toxoplasma infection among population in Xuhui district of Shanghai city using the recombinant Toxoplasma gondii surface protein SAG1.Methods: Recombinant plasmids pET19b-SAG1 were expressed in E.coli BL21 star(DE3) pLysS.After purification by Ni2+ gel column chromatography,the antigenicity of recombinant SAG1 was confirmed.The specific IgG antibodies against recombinant SAG1 in the sera of people(266 cases) in Xuhui district were detected by ELISA,and confirmed by foreign diagnostic kit.Results: 0.98 mg recombinant SAG1 with a purity as high as 95% were obtained in 100ml medium and existed in a form of inclusion body.It showed good antigenicity.Serological surveillance of Toxoplasma infection in Xuhui district using the recombinant SAG1 showed positive rate of 9.4%(25/266).Conclusion: Recombinant SAG1 was expressed successfully with relatively high specificity.The positive rate of anti-toxoplasma IgG in people in Xuhui district of Shanghai city was 9.4%.It was suggested that serological monitoring should be employed,so that effective intervention methods can be used in time.

OBJECTIVE To investigate and analyze an outbreak of nosocomial norovirus GⅡ gastroenteritis in a medical ward.METHODS Field epidemiology was conducted using a standard questionnaire,and case-control study method was applied to analyze the risk factors.RT-PCR was performed for norovirus detection.RESULTS A total of 22 cases were reported during the outbreak,and the incidence rate was 31.0%.The outbreak lasted for 8 days with vomit and diarrhea as the clinical characteristics,and the introduction rate was 30.3%.The distribution of outbreak showed a single-peak epidemic curve with time in horizontal axis and trend of space aggregation.2 cases were identified by laboratory diagnostic.9 out of 11 stool specimens were submitted positive using a RT-PCR method,while 6 environmental samples were all negative.The OR was 11.2(OR 95% CI=1.80~116.80) exposed to subclinical infected HCWs,and the difference was statistically significant(χ2=4.98 P=0.0260.05).The aggregative space distribution was consistent with the high attack rate associated with exposure to subclinical infected HCW.CONCLUSION The gastroenteritis outbreak in healthcare setting is caused by norovirus GⅡ.Subclinical infected HCWs are important sources of transmission;and direct contact is one of major transmission route.The spread of norovirus infection can be effectively curbed through implement of disinfection and isolation precautions.To actively promote adherence to hand hygiene and PPE use to contact and standard precautions has an important role in prevention and control of norovirus gastroenteritis outbreak in healthcare settings.

Vibrio cholerae infection leads to severe diarrhea as part of cholera and has the potential to cause a worldwide pandemic.Speedy and accurate detection of Vibrio cholerae is critical for the prevention and control of cholera.So far,many effective diagnostic methods have been established.The application of molecular biotechnology in the identification of Vibrio cholerae has made major changes in this area.The current review discusses the recent advances in the detection technology of Vibrio cholerae.